It's widely considered to be the primary factor in Don Prudomme's US Nats 5.63 when everyone else was 2 tenths slower. I don't recall Snake definitively saying yes or no and from reading posts from racers back in the day, opinions are divided. Some say Snake ran nitrous/nitro; Snake himself said the nitrous bottle was a decoy along the lines of Bernstein's 'terrible towel'. Others say Snake hit on a tune and a clutch setup that just clicked, hence the .63.
But whatever. Some things are better off left alone and hydrazine, as everyone found out, is one of them.